title: Natural sequence variants of yeast environmental sensors confer cell-to-cell expression variability.
abstract: Living systems may have evolved probabilistic bet hedging strategies that generate cell-to-cell phenotypic diversity in anticipation of environmental catastrophes, as opposed to adaptation via a deterministic response to environmental changes. Evolution of bet hedging assumes that genotypes segregating in natural populations modulate the level of intraclonal diversity, which so far has largely remained hypothetical. Using a fluorescent P(met17)-GFP reporter, we mapped four genetic loci conferring to a wild yeast strain an elevated cell-to-cell variability in the expression of MET17, a gene regulated by the methionine pathway. A frameshift mutation in the Erc1p transmembrane transporter, probably resulting from a release of laboratory strains from negative selection, reduced P(met17)-GFP expression variability. At a second locus, cis-regulatory polymorphisms increased mean expression of the Mup1p methionine permease, causing increased expression variability in trans. These results demonstrate that an expression quantitative trait locus (eQTL) can simultaneously have a deterministic effect in cis and a probabilistic effect in trans. Our observations indicate that the evolution of transmembrane transporter genes can tune intraclonal variation and may therefore be implicated in both reactive and anticipatory strategies of adaptation.
authors.affiliation: Laboratoire de Biologie Moléculaire de la Cellule, Ecole Normale Supérieure de Lyon, CNRS, Université Lyon 1, Lyon, France.
authors.forename: Steffen
authors.initials: S
authors.lastname: Fehrmann
authors.forename: Hélène
authors.initials: H
authors.lastname: Bottin-Duplus
authors.forename: Andri
authors.initials: A
authors.lastname: Leonidou
authors.forename: Esther
authors.initials: E
authors.lastname: Mollereau
authors.forename: Audrey
authors.initials: A
authors.lastname: Barthelaix
authors.forename: Wu
authors.initials: W
authors.lastname: Wei
authors.forename: Lars M
authors.initials: LM
authors.lastname: Steinmetz
authors.forename: Gaël
authors.initials: G
authors.lastname: Yvert
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D005075:Biological Evolution; D003547:Cysteine Synthase / Q000235:genetics* / Q000378:metabolism; D004777:Environment; D016368:Frameshift Mutation; D015966:Gene Expression Regulation, Fungal; D059647:Gene-Environment Interaction; D017930:Genes, Reporter; D008040:Genetic Linkage; D014644:Genetic Variation; D005838:Genotype; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D040641:Quantitative Trait Loci; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D026901:Membrane Transport Proteins; D011506:Proteins; D029701:Saccharomyces cerevisiae Proteins; C035737:major urinary proteins; D049452:Green Fluorescent Proteins; D003547:Cysteine Synthase; C103381:MET17 protein, S cerevisiae